Cowpea mosaic virus
Encyclopedia
Cowpea mosaic virus is a plant virus
of the comovirus
group. Infection of a susceptible cowpea
leaf
results in high virus yields (1-2 g/kg). Its Genome
consists of 2 molecules of positive-sense
RNA
(RNA-1 and RNA-2) which are separately encapsidated. Both RNA1 and RNA2 have a VPg
(virus genome-linked protein) at the 5'end, and polyadenylation
at the 3' end. Genomic RNA1 and RNA2 are expressed by a polyprotein processing strategy. RNA1 encodes helicase
, VPg, protease
and RdRp
. RNA2 encodes movement protein
and coat protein
. The virus particles are 28 nm in diameter and contain 60 copies each of a Large (L) and Small (S) coat protein. The structure is well characterised to atomic resolution, and the viral particles are thermostable.
CPMV displays a number of features that can be exploited for nanoscale biomaterial fabrication. Its genetic
, biological and physical properties are well characterised, and it can be isolated readily from plants. There are many stable mutants already prepared that allow specific modification of the capsid
surface. It is possible to attach a number of different chemicals to the virus surface and to construct multilayer arrays of such nanoparticle
s on solid surfaces. This gives the natural or genetically engineered nanoparticles a range of properties which could be useful in nanotechnological applications such as biosensor
s, catalysis
and nanoelectronic devices.
One example use of CPMV particles is to amplify signals in microarray
based sensors. In this application, the virus particles separate the fluorescent
dye
s used for signaling in order to prevent the formation of non-fluorescent dimers that act as quenchers
. Another example is the use of CPMV as a nanoscale breadboard
for molecular electronics.
Plant virus
Plant viruses are viruses that affect plants. Like all other viruses, plant viruses are obligate intracellular parasites that do not have the molecular machinery to replicate without a host. Plant viruses are pathogenic to higher plants...
of the comovirus
Comoviridae
The Comovirinae are a subfamily within the family Secoviridae in the order of Picornavirales, including the following genera:*Genus Comovirus; type species: Cowpea mosaic virus*Genus Fabavirus; type species: Broad bean wilt virus 1...
group. Infection of a susceptible cowpea
Cowpea
The Cowpea is one of several species of the widely cultivated genus Vigna. Four cultivated subspecies are recognised:*Vigna unguiculata subsp. cylindrica Catjang...
leaf
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
results in high virus yields (1-2 g/kg). Its Genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
consists of 2 molecules of positive-sense
Sense (molecular biology)
In molecular biology and genetics, sense is a concept used to compare the polarity of nucleic acid molecules, such as DNA or RNA, to other nucleic acid molecules...
RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
(RNA-1 and RNA-2) which are separately encapsidated. Both RNA1 and RNA2 have a VPg
VPg
VPg is a protein attached to the 5' end of RNA during RNA synthesis in a wide variety of viruses including Picornaviridae such as Foot-and-mouth disease and poliovirus . VPg stands for "viral protein genome-linked".-Attachment during RNA synthesis:...
(virus genome-linked protein) at the 5'end, and polyadenylation
Polyadenylation
Polyadenylation is the addition of a poly tail to an RNA molecule. The poly tail consists of multiple adenosine monophosphates; in other words, it is a stretch of RNA that has only adenine bases. In eukaryotes, polyadenylation is part of the process that produces mature messenger RNA for translation...
at the 3' end. Genomic RNA1 and RNA2 are expressed by a polyprotein processing strategy. RNA1 encodes helicase
Helicase
Helicases are a class of enzymes vital to all living organisms. They are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separating two annealed nucleic acid strands using energy derived from ATP hydrolysis.-Function:Many cellular processes Helicases are a...
, VPg, protease
Protease
A protease is any enzyme that conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain forming the protein....
and RdRp
RNA-dependent RNA polymerase
RNA-dependent RNA polymerase , , or RNA replicase, is an enzyme that catalyzes the replication of RNA from an RNA template...
. RNA2 encodes movement protein
Movement Proteins
Successful infection of a plant by a plant virus depends on its ability to move from the cell initially infected to neighbouring cells in order to spread infection. Unlike animal cells, plant cells have robust cell walls, which viruses cannot easily penetrate...
and coat protein
Capsid
A capsid is the protein shell of a virus. It consists of several oligomeric structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The capsid encloses the genetic...
. The virus particles are 28 nm in diameter and contain 60 copies each of a Large (L) and Small (S) coat protein. The structure is well characterised to atomic resolution, and the viral particles are thermostable.
CPMV displays a number of features that can be exploited for nanoscale biomaterial fabrication. Its genetic
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
, biological and physical properties are well characterised, and it can be isolated readily from plants. There are many stable mutants already prepared that allow specific modification of the capsid
Capsid
A capsid is the protein shell of a virus. It consists of several oligomeric structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The capsid encloses the genetic...
surface. It is possible to attach a number of different chemicals to the virus surface and to construct multilayer arrays of such nanoparticle
Nanoparticle
In nanotechnology, a particle is defined as a small object that behaves as a whole unit in terms of its transport and properties. Particles are further classified according to size : in terms of diameter, coarse particles cover a range between 10,000 and 2,500 nanometers. Fine particles are sized...
s on solid surfaces. This gives the natural or genetically engineered nanoparticles a range of properties which could be useful in nanotechnological applications such as biosensor
Biosensor
A biosensor is an analytical device for the detection of an analyte that combines a biological component with a physicochemical detector component.It consists of 3 parts:* the sensitive biological element A biosensor is an analytical device for the detection of an analyte that combines a biological...
s, catalysis
Catalysis
Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations....
and nanoelectronic devices.
One example use of CPMV particles is to amplify signals in microarray
Microarray
A microarray is a multiplex lab-on-a-chip. It is a 2D array on a solid substrate that assays large amounts of biological material using high-throughput screening methods.Types of microarrays include:...
based sensors. In this application, the virus particles separate the fluorescent
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...
dye
Dye
A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and requires a mordant to improve the fastness of the dye on the fiber....
s used for signaling in order to prevent the formation of non-fluorescent dimers that act as quenchers
Quenching (fluorescence)
Quenching refers to any process which decreases the fluorescence intensity of a given substance. A variety of processes can result in quenching, such as excited state reactions, energy transfer, complex-formation and collisional quenching. As a consequence, quenching is often heavily dependent on...
. Another example is the use of CPMV as a nanoscale breadboard
Breadboard
A breadboard is a construction base for prototyping of electronics. The term is commonly used to refer to solderless breadboard ....
for molecular electronics.
External links
- http://dx.doi.org/10.1002/elps.200306029Separation and recovery of intact gold-virus complex by agarose electrophoresis and electroelutionElectroelutionElectroelution is a method used to extract a nucleic acid or a protein sample from an electrophoresis gel by applying a negative current in the plane of the smallest dimension of the gel, drawing the macromolecule to the surface for extraction and subsequent analysis...
: Application to the purification of cowpea mosaic virus and colloidal gold complex] - ICTVdB - The Universal Virus Database: Cowpea mosaic virus
- Family Groups - The Baltimore Method
- ICTV Virus Taxonomy 2009 http://www.ictvonline.org
- UniProt Taxonomy